THIS invention relates to a punch device.
There are many applications in which it is necessary or desirable to have a device capable of reliably breaking a pane or sheet of glass, such as that in a window or glass door. This may for example be for emergency purposes where it necessary to break the glass in order to create an emergency exit.
One common application is in motor vehicles such as buses where a rear window or other window of the vehicle provides an emergency exit from the vehicle. Another common application is in fire alarm installations where a fire alarm is housed in a wall-mounted box covered by a glass window. Yet further common applications are in boats where it may be necessary to break a window in order to gain rapid exit from the vessel.
Traditionally a loose hammer or other heavy impact tool is provided in the vicinity of the glass sheet to enable a person to break the glass sheet by hammering on it. However, hammers or other loose tools can easily be removed, lost or stolen. Apart from this, the type of impact which a relatively blunt tool such as a hammer can apply to a glass sheet is very often insufficient to break certain types of glass, and in particular the toughened glass sheets normally used in motor vehicles. This is primarily because glass sheets of this type have extremely tough external skins which are not easily penetrated.
The specification of South African patent 91/8034 describes devices which can be fitted on a glass pane or sheet, such as a vehicle window, and which can be actuated to break the glass in an emergency situation.
Apart from the fact that these devices have a number of moving parts and fairly complicated constructions, they have the disadvantage that they have fairly large dimensions and hence stand out quite some distance from the window or other glass sheet on which they are fitted. This means that they can present an obstacle to persons close to the window or glass sheet.
The present invention seeks to provide a simpler device of relatively squat proportions.